The invention relates to closures for bottles and other types of containers in general, and more particularly to improvements in closures with tamper indicating devices in the form of bands or rings which are used on filled containers to facilitate immediate determination of the condition of the container, namely whether or not the contents of the container are intact and are still packaged in a manner as provided for by the manufacturer.
Closures with tamper indicating bands are often made of thermoplastic material and are used on many types of bottles or other threaded-neck containers in order to enable a potential purchaser or user to rapidly and reliably ascertain whether or not the container was tampered with subsequent to original filling and sealing. The purpose of such bands or rings is to ensure that their condition changes so drastically in response to first opening of the container (i.e., in response to partial or complete removal of the closure) that this fact cannot be concealed even from a casual observer.
The majority of heretofore known tamper indicating devices constitute or resemble bands which are connected to the skirts of the respective bottle caps or like closures by a plurality of narrow bridges or webs. The inner and outer diameters of the band normally match or closely approximate the respective diameters of the skirt of the cap. When the cap is properly applied to the neck of a bottle or another threaded-neck container (e.g., in that its internal threads mate with the external threads on the neck), the band is heated and shrunk onto the adjacent portion of the neck beneath the thread so that it closely hugs the external surface of the neck and the bridges or webs are caused to break when the cap is unscrewed. In order to further reduce the likelihood of separation of the band jointly with the cap, the neck of the bottle is normally provided with a larger-diameter bead beneath the external thread and the band is shrunk onto and extends beyond the bead in a direction away from the thread so as to invariably ensure reliable destruction of the bridges in response to unscrewing of the cap. In other words, when the cap is detached, the band remains on the neck of the bottle.
A drawback of the just described tamper indicating devices is that the band can be expanded in response to heating or that its flexibility greatly increases in response to heating so that it can be detached with the cap and, if desired, reapplied and shrunk back onto the bead. In fact, even body heat often suffices to soften the band if the latter is held in hand for a sufficient interval of time. Another drawback of such bands is that they normally remain on the necks of the containers so that, if the containers are to be recycled, it is necessary to remove the bands from the necks in a separate time-consuming operation which precedes the refilling and the application of a fresh (intact) closure.
French Pat. No. 2 454 977 to Perne et al. discloses a modified tamper indicating band which breaks in response to detachment of the closure from a container and remains attached to the skirt of the closure. Several separable sections of the band are connected to each other by weakened portions (also called rupture sites) which are easy to break and are supposed to break when the closure is detached from the container. A drawback of the patented closure is that the band tends to break in response to the very first application of the closure so that the damaged or destroyed band creates the impression of previous tampering with the container even though the contents of the container are still intact.